C

• Computational problems‎ (12 C, 30 P)

M

• Mathematical paradoxes‎ (5 C, 41 P)
• Mathematical theorems‎ (18 C, 44 P)

P

• Packing problems‎ (2 C, 29 P)
• Probability problems‎ (31 P)

S

• Squaring the circle‎ (9 P)

T

• Triangle problems‎ (6 P)

U

• Undecidable problems‎ (23 P)
• Unsolvable puzzles‎ (12 P)
• Unsolved problems in mathematics‎ (6 C, 77 P)

• Mathematical problem

A

• Alhazen's problem

B

• Basel problem
• Behrens–Fisher problem
• Birthday problem
• Block-stacking problem
• Boolean Pythagorean triples problem
• Boundary value problem
• Bristol Bridges Walk

C

• Carpenter's rule problem
• Cauchy problem
• Cheryl's Birthday
• Circulation problem
• Class number problem
• Clock angle problem
• Congruence lattice problem

D

• Dining cryptographers problem
• Dirichlet problem
• Dissection problem
• Dividing a square into similar rectangles

E

• Eight queens puzzle
• Erdős discrepancy problem

F

• Finite lattice representation problem
• Finite volume method for three-dimensional diffusion problem
• Firing squad synchronization problem

H

• Hadwiger–Nelson problem
• Halting problem
• Hamburger moment problem
• Hansen's problem
• Happy ending problem
• Hausdorff moment problem
• Hurwitz problem

I

• Illumination problem
• Invariant subspace problem

J

• Josephus problem

K

• Kirkman's schoolgirl problem
• Klee's measure problem
• Knight's tour
• Kuratowski's closure-complement problem

L

• Lattice problem
• Littlewood–Offord problem

M

• Minimum-cost flow problem
• Moment problem
• The monkey and the coconuts
• Monty Hall problem
• Mountain climbing problem
• Mrs. Miniver's problem

N

• Napkin ring problem
• Napoleon's problem
• Necklace splitting problem
• Network simplex algorithm
• Newton–Pepys problem
• Newton's minimal resistance problem
• No-three-in-line problem

O

• Oberwolfach problem
• Orchard-planting problem

P

• Parity problem (sieve theory)
• Plateau's problem
• Postage stamp problem
• Prescribed Ricci curvature problem
• Prescribed scalar curvature problem
• Prouhet–Tarry–Escott problem

R

• Regiomontanus' angle maximization problem
• Riemann–Hilbert problem
• Rope-burning puzzle

S

• Schoenflies problem
• Seven Bridges of Königsberg
• Snellius–Pothenot problem
• Social golfer problem
• Spherical Bernstein's problem
• Square trisection
• Squaring the square
• Stable marriage problem
• Stable roommates problem
• Stieltjes moment problem

T

• Tarski's circle-squaring problem
• Traveling tournament problem
• Turán's brick factory problem

V

• Vertex enumeration problem

W

• Waring's problem
• Water pouring puzzle
• Whitehead problem

Y

• Yamabe problem

Z

• Zarankiewicz problem
• Zero-sum problem
• Znám's problem